ICU Map
ICU Medication MasterclassPK/PD • Resistance • Site • Source control • De-escalation

Antimicrobial Pharmacology & Stewardship

A pharmacology-first companion to ICU Antimicrobial Strategy: choose empiric therapy by syndrome and resistance risk, then optimize exposure by PK/PD, organ support and source control before narrowing from microbiology.

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1

Separate empiric syndrome coverage from definitive organism-directed therapy.

2

Use beta-lactam time-above-MIC, aminoglycoside concentration-dependent killing and vancomycin AUC concepts correctly.

3

Recognize when augmented renal clearance, AKI, CRRT, IHD, obesity or ECMO can change exposure.

4

Reserve newer beta-lactam/beta-lactamase inhibitor combinations and cefiderocol for the resistant phenotypes where they add value.

5

Treat source control and de-escalation as medication decisions, not afterthoughts.

Open ICU Antimicrobial Strategy

Syndrome-based empiric → culture → de-escalation pathways.

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Medication Challenges

Practice antimicrobial and organ-failure medication decisions.

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Core agents

Choose by physiology, not by habit

The table below is a selection framework. Open the individual monograph for exact dosing, preparation, renal/CRRT/IHD adjustment, interactions and evidence traceability.

Piperacillin–Tazobactam
Antipseudomonal Penicillin & Beta-Lactamase Inhibitor
Core agent

ICU role: Broad empiric beta-lactam for many severe polymicrobial/Gram-negative syndromes when local susceptibility supports it.

Choose: Useful when Pseudomonas plus anaerobic coverage is desired and resistance risk is not pushing toward a carbapenem/newer agent.
Hesitate: Not a universal ESBL/CRE solution; avoid treating a resistant phenotype by spectrum name alone.

Monitor: Renal function, sodium load, infusion strategy, cultures/source control.

Cefepime
4th-Generation Cephalosporin Antibiotic
Core agent

ICU role: Antipseudomonal cephalosporin for severe Gram-negative infection when anaerobic coverage is not required.

Choose: Useful for susceptible Pseudomonas and many hospital-acquired infections; often paired with separate anaerobic coverage when needed.
Hesitate: Neurotoxicity risk rises with renal dysfunction/excess exposure; does not cover anaerobes or Enterococcus.

Monitor: Renal trajectory, mental status, dosing interval/infusion strategy.

Meropenem
Group 2 Antipseudomonal Carbapenem Antibiotic
Core agent

ICU role: Carbapenem for severe ESBL-risk infection and selected broad empiric ICU syndromes.

Choose: High-reliability option for serious ESBL-producing Enterobacterales outside simple cystitis and severe polymicrobial sepsis.
Hesitate: Do not use merely because the patient is sick if a narrower active beta-lactam is adequate; carbapenem resistance changes the strategy.

Monitor: Renal/CRRT exposure, seizures/neurotoxicity, culture-driven de-escalation.

Vancomycin
Glycopeptide Antibiotic
Core agent

ICU role: IV MRSA and other serious susceptible Gram-positive coverage.

Choose: Empiric MRSA coverage when the syndrome/risk warrants it; definitive therapy for susceptible MRSA when appropriate.
Hesitate: AUC-guided exposure and nephrotoxicity matter; not active against Gram-negatives and not preferred for every MSSA infection.

Monitor: AUC/TDM strategy, creatinine/urine output, culture susceptibility.

Linezolid
Oxazolidinone Antibiotic
Core agent

ICU role: MRSA/VRE-active oxazolidinone with excellent lung penetration and full oral bioavailability.

Choose: Useful in selected MRSA pneumonia and VRE infections where site/organ profile favors it.
Hesitate: Myelosuppression, serotonergic interactions and prolonged-course toxicity; not a bactericidal substitute for every bloodstream/endovascular infection.

Monitor: CBC, interaction review, neuropathy/lactate with prolonged use.

Ceftazidime-Avibactam
Cephalosporin / beta-lactamase inhibitor
Core agent

ICU role: Newer beta-lactam/beta-lactamase inhibitor active against KPC and OXA-48-like CRE, among other susceptible organisms.

Choose: Preferred option for OXA-48-like Enterobacterales in IDSA 2026 AMR guidance when active; also used for susceptible KPC CRE.
Hesitate: Does not cover metallo-beta-lactamases alone; resistance can emerge.

Monitor: Mechanism/susceptibility, renal dosing, microbiologic response.

Ceftolozane-Tazobactam
Cephalosporin / beta-lactamase inhibitor
Core agent

ICU role: Potent antipseudomonal beta-lactam/beta-lactamase inhibitor for susceptible difficult-to-treat Pseudomonas.

Choose: Useful when resistant Pseudomonas remains susceptible and the infection site is appropriate.
Hesitate: Not a general CRE drug and activity depends on the resistance mechanism.

Monitor: Susceptibility, renal function, clinical/microbiologic response.

Meropenem-Vaborbactam
Carbapenem / beta-lactamase inhibitor
Core agent

ICU role: Carbapenem/beta-lactamase inhibitor with strong activity against KPC-producing CRE.

Choose: Mechanism-directed definitive option for susceptible KPC CRE.
Hesitate: Vaborbactam does not solve OXA-48-like or MBL resistance.

Monitor: Mechanism/susceptibility, renal/CRRT dosing, recurrence/resistance.

Imipenem-Cilastatin-Relebactam
Carbapenem / dehydropeptidase-I inhibitor / beta-lactamase inhibitor
Core agent

ICU role: Carbapenem/relebactam combination active against selected KPC CRE and resistant Pseudomonas.

Choose: Useful when susceptibility and resistance mechanism fit the drug.
Hesitate: Not reliable for MBL or OXA-48-like producers.

Monitor: Renal function, CNS adverse effects, susceptibility.

Cefiderocol
Siderophore cephalosporin
Core agent

ICU role: Siderophore cephalosporin with activity against many highly resistant Gram-negative organisms.

Choose: Preferred/important option in selected MBL-producing Enterobacterales and difficult resistant Gram-negative infections when susceptibility supports it.
Hesitate: Do not deploy as a generic broad-spectrum substitute; outcome data and organism-specific guidance matter.

Monitor: Susceptibility, infection site, microbiologic response, renal function.

Sulbactam-Durlobactam
Penicillin-binding antibacterial / beta-lactamase inhibitor
Core agent

ICU role: Preferred sulbactam-based treatment backbone for carbapenem-resistant A. baumannii (CRAB).

Choose: IDSA 2026 prefers sulbactam-durlobactam with imipenem-cilastatin or meropenem for invasive CRAB. If it is not immediately available, high-dose ampicillin-sulbactam plus another active agent is temporary bridge therapy only.
Hesitate: CRAB treatment remains organism- and severity-specific; do not extrapolate to unrelated resistant Gram-negatives.

Monitor: Susceptibility, renal function, source control, clinical response.

Trimethoprim–Sulfamethoxazole (TMP-SMX)
Sulfonamide & Folate Antagonist Combination
Core agent

ICU role: Key therapy for susceptible Stenotrophomonas, Pneumocystis and several other infections.

Choose: High-value when the organism/syndrome fits rather than as undifferentiated broad empiric coverage.
Hesitate: Hyperkalemia, AKI/creatinine effects, marrow suppression and dose complexity in renal dysfunction.

Monitor: Potassium, creatinine, CBC, renal dosing.

Amikacin
Aminoglycoside Antibiotic
Core agent

ICU role: Concentration-dependent aminoglycoside used selectively for resistant Gram-negative infection or synergistic strategy.

Choose: Can provide rapid active Gram-negative coverage when susceptibility supports it and alternatives are limited.
Hesitate: Nephrotoxicity/ototoxicity; avoid prolonged empiric continuation without a specific reason.

Monitor: TDM when used beyond a limited course, renal function, hearing/vestibular toxicity.

Micafungin
Echinocandin antifungal
Core agent

ICU role: Echinocandin commonly used as initial candidemia/invasive candidiasis therapy in critically ill adults.

Choose: Reliable initial Candida coverage in unstable ICU patients while species/susceptibility are pending.
Hesitate: Not adequate for every CNS/urinary/ocular Candida problem; step-down depends on susceptibility and clinical stability.

Monitor: Liver tests, species/susceptibility, clearance of blood cultures/source control.

Liposomal Amphotericin B
Polyene Antifungal Agent (Liposomal Formulation)
Core agent

ICU role: Broad fungicidal therapy for selected invasive mold/yeast infections and resistant fungal disease.

Choose: Essential for mucormycosis and selected severe invasive fungal syndromes.
Hesitate: Nephrotoxicity and electrolyte wasting remain important even with liposomal formulation.

Monitor: Creatinine, potassium, magnesium, infusion reactions.

Clinical decision matrix

What changes the drug choice?

Septic shock, source uncertain

Preferred reasoning: Obtain cultures without delaying therapy, choose empiric agents from syndrome + local antibiogram + prior organisms, and pursue source control in parallel.
Avoid: A universal 'sepsis cocktail' that ignores prior cultures, anatomic source, resistance risk and renal support.

Why: Severity determines urgency; anatomy and ecology determine spectrum. Reassess daily and narrow once data arrive.

Serious ESBL-producing Enterobacterales outside uncomplicated cystitis

Preferred reasoning: A carbapenem is often the most reliable definitive beta-lactam; preserve newer agents for carbapenem-resistant organisms when possible.
Avoid: Escalating automatically to the newest beta-lactam/beta-lactamase inhibitor when meropenem is active and clinically appropriate.

Why: IDSA AMR guidance preferentially reserves newer agents for carbapenem-resistant phenotypes.

NDM / other metallo-beta-lactamase CRE

Preferred reasoning: Ceftazidime-avibactam + aztreonam or cefiderocol, guided by susceptibility and local availability.
Avoid: Meropenem-vaborbactam or imipenem-relebactam simply because they are 'new CRE drugs'.

Why: Serine beta-lactamase inhibitors do not inhibit MBLs; aztreonam is stable to MBL hydrolysis but needs protection from co-produced serine enzymes.

OXA-48-like CRE

Preferred reasoning: Ceftazidime-avibactam when active; cefiderocol is an alternative.
Avoid: Assuming vaborbactam/relebactam reliably inhibit OXA-48-like enzymes.

Why: Resistance mechanism matters more than brand familiarity.

CRAB pneumonia/bacteremia

Preferred reasoning: For invasive CRAB, prefer sulbactam-durlobactam with meropenem or imipenem-cilastatin. If unavailable, use high-dose ampicillin-sulbactam plus another active agent only as temporary bridge therapy.
Avoid: Polymyxin monotherapy or treating CRAB like generic CRE.

Why: Sulbactam has direct A. baumannii PBP activity; durlobactam protects it against important beta-lactamases.

NDM-producing CRAB

Preferred reasoning: Use an IDSA 2026 non-sulbactam-based combination strategy guided by susceptibility (for example selected combinations using cefiderocol, minocycline, polymyxin B or tigecycline).
Avoid: Assuming sulbactam-durlobactam will overcome an NDM/metallo-beta-lactamase mechanism.

Why: Durlobactam inhibits class A/C/D enzymes but not class B MBLs such as NDM; mechanism-directed treatment is required.

Candidemia in an unstable ICU patient

Preferred reasoning: An echinocandin is a common initial choice plus prompt line/source evaluation and follow-up blood cultures.
Avoid: Fluconazole reflexively before considering instability, species, prior azole exposure and susceptibility.

Why: Initial drug, source control and later step-down are separate decisions.

High-yield protocols

Mechanism-based sequences worth memorizing

Beta-lactam exposure

  1. Most beta-lactams are time-dependent; prolonged/extended infusion can improve target attainment in selected critically ill patients.
  2. Loading and early adequate exposure matter most in severe infection; maintenance should follow evolving clearance.
  3. Do not equate a susceptible MIC with guaranteed exposure in ARC or high-volume states.

Aminoglycoside exposure

  1. Aminoglycosides are concentration-dependent; adequate peak exposure and toxicity-limited duration are central.
  2. Use weight, renal function and TDM rather than a fixed empiric interval in unstable ICU physiology.
  3. Do not continue a nephrotoxic second Gram-negative agent once it no longer adds value.

Stewardship checkpoint at 48–72 h

  1. Reconcile cultures, source, imaging, clinical trajectory and microbiology.
  2. Narrow or stop unnecessary components; convert to the simplest active regimen.
  3. Define duration from syndrome, source control and response—not from habit.
⚠️ Broad is not better once microbiology and source are known.

Antimicrobial subtracks

  1. Standard beta-lactams: ampicillin, penicillin G, cefazolin, cefepime, piperacillin-tazobactam and carbapenems—choose by syndrome, allergy, source and susceptibility.
  2. Resistant Gram-negatives: newer beta-lactam/beta-lactamase inhibitors, cefiderocol, aminoglycosides/polymyxins and tetracycline derivatives—use mechanism-directed therapy.
  3. Gram-positive rescue: vancomycin, linezolid and daptomycin—site, MIC/susceptibility, lung surfactant and bloodstream/endovascular context matter.
  4. Antifungals/antivirals: echinocandins, azoles, amphotericin, oseltamivir/remdesivir/foscarnet—organ function and site-specific penetration are central.
⚠️ Every antimicrobial monograph remains linked below; the Masterclass teaches selection, not one-size-fits-all dosing.
Organ failure & special settings

When standard pharmacology stops being standard

Augmented renal clearance
Priority: Recognize unexpectedly high beta-lactam/vancomycin clearance in young hyperdynamic ICU patients and use exposure-focused dosing/TDM where available.
Pitfall: Reducing doses simply because the patient is critically ill or because creatinine looks 'normal'.
Rapidly changing AKI
Priority: Separate loading dose from maintenance; many hydrophilic antimicrobials still need an adequate initial dose despite AKI, then maintenance is adjusted as clearance evolves.
Pitfall: Under-loading a septic patient because renal function is impaired.
CRRT / IHD
Priority: Use the actual modality, effluent/dialysis prescription, residual kidney function and TDM when possible.
Pitfall: Applying one fixed 'CRRT dose' to every circuit and effluent rate.
ECMO / obesity / large Vd
Priority: Consider altered volume of distribution and adsorption for selected agents, but prioritize clinical/TDM data rather than assuming every drug needs an ECMO multiplier.
Pitfall: Automatic empiric dose inflation without drug-specific evidence.
CNS infection
Priority: Choose agents with appropriate CNS penetration and inflammation-dependent pharmacology; source and pathogen still matter.
Pitfall: Using a drug with great serum susceptibility but poor CNS exposure.
Source control
Priority: Drain, debride, remove infected hardware/catheters when indicated; drug escalation cannot compensate for an uncontrolled source.
Pitfall: Calling persistent bacteremia 'antibiotic failure' before reassessing the source.
Resident progression

R1 → R5 bedside cases

Recognition becomes selection, then organ-failure adjustment, competing physiology and senior-level prioritization.

R1

Empiric coverage is not definitive therapy

A patient with septic shock and suspected urinary source receives broad empiric therapy. Blood and urine cultures later grow susceptible E. coli with no ESBL mechanism.

Show reasoning

Narrow to the simplest active definitive regimen once stability, susceptibilities and source are clear. Continuing the broadest regimen 'because the patient was sick' is not stewardship.

R2

ARC and beta-lactam failure

A young trauma patient with pneumonia has CrCl >130 mL/min and persistent fevers despite a susceptible beta-lactam given by short intermittent infusion.

Show reasoning

Consider augmented renal clearance and inadequate exposure, verify source/culture, then optimize dose/infusion strategy according to the monograph/local protocol rather than reflexively changing drug class.

R3

KPC versus MBL

Two CRE isolates look similarly resistant on the antibiogram. One carries KPC; the other carries NDM.

Show reasoning

Mechanism changes the drug choice. KPC can be treated with active KPC-directed newer beta-lactams; NDM/MBL requires a strategy such as ceftazidime-avibactam + aztreonam or cefiderocol when susceptible.

R4

CRAB in ventilator pneumonia

A ventilated patient has CRAB pneumonia with shock and the isolate is susceptible to sulbactam-durlobactam. Renal function is changing on CRRT.

Show reasoning

Build around sulbactam-containing therapy—preferably sulbactam-durlobactam plus meropenem/imipenem-cilastatin per current IDSA guidance—then individualize maintenance exposure to the CRRT prescription and reassess source/response.

R5

Culture result versus patient phenotype

A patient initially improves from septic shock, then remains vasopressor-dependent despite sterile repeat cultures. The team proposes escalating from meropenem to cefiderocol solely because lactate remains elevated.

Show reasoning

Do not treat persistent shock as proof of resistant infection. Reassess source control, cardiac function, vasoplegia, ischemia, drug toxicity and noninfectious causes. Antimicrobial escalation should follow organism/resistance evidence, not lactate alone.

Full medication monograph

Piperacillin–Tazobactam

Workhorse ICU antipseudomonal penicillin providing broad Gram-negative, Gram-positive, and anaerobic coverage — best administered as an extended 4-hour infusion, but carries synergy for AKI when combined with Vancomycin.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Cefepime

Zwitterionic 4th-generation antipseudomonal cephalosporin with useful activity against susceptible Pseudomonas and many AmpC-producing Enterobacterales; it is one accepted option for syndromes such as HAP/VAP or febrile neutropen…

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Meropenem

Ultra-broad-spectrum antipseudomonal Group 2 carbapenem for severe ESBL Enterobacterales, MDR Pseudomonas aeruginosa, intra-abdominal sepsis, and post-neurosurgical meningitis.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Vancomycin

Parenteral glycopeptide for serious susceptible Gram-positive infections, especially MRSA; in serious invasive MRSA, use an appropriate loading strategy when rapid exposure is needed and AUC-guided monitoring (target AUC24/MIC 40…

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Linezolid

Synthetic oxazolidinone active against MRSA and VRE, with excellent oral bioavailability and useful lung penetration. Standard labeling does not mandate renal dose adjustment, but renal dysfunction and prolonged exposure increase…

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Ceftazidime-Avibactam

Key agent for selected CRE and DTR Pseudomonas; active against KPC and OXA-48-like enzymes but not metallo-beta-lactamases by itself.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Ceftolozane-Tazobactam

Potent antipseudomonal beta-lactam/beta-lactamase inhibitor, particularly valuable for DTR Pseudomonas pneumonia and other severe infections.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Meropenem-Vaborbactam

Carbapenem plus boronic-acid beta-lactamase inhibitor, preferred for KPC-producing Enterobacterales but inactive against MBLs and OXA-48-like enzymes.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Imipenem-Cilastatin-Relebactam

Carbapenem/beta-lactamase-inhibitor option for selected KPC-producing Enterobacterales and susceptible DTR Pseudomonas; relebactam inhibits class A (including KPC) and class C beta-lactamases but not metallo-beta-lactamases or OX…

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Cefiderocol

Siderophore cephalosporin active against many carbapenem-resistant Gram-negative organisms, including MBL producers. IDSA 2026 also identifies cefiderocol monotherapy as the preferred approach for invasive Stenotrophomonas maltop…

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Sulbactam-Durlobactam

FDA-approved as Xacduro for HABP/VABP caused by susceptible A. baumannii-calcoaceticus complex. IDSA 2026 extends its role to preferred therapy for invasive CRAB when combined with imipenem-cilastatin or meropenem; durlobactam pr…

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Trimethoprim–Sulfamethoxazole (TMP-SMX)

Sequential folate pathway inhibitor used for Pneumocystis jirovecii pneumonia (PJP), selected susceptible bacterial infections, Nocardia, and as an active option for Stenotrophomonas maltophilia. Doses are conventionally expresse…

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Amikacin

Potent concentration-dependent aminoglycoside for severe MDR Gram-negative bacilli and Pseudomonas aeruginosa — requires distinguishing Product-Label Conventional Dosing from Critical Care Extended-Interval PK Strategies, therape…

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Micafungin

Echinocandin used for candidemia/invasive candidiasis; the U.S. label requires no renal dose adjustment and no post-hemodialysis supplement.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Liposomal Amphotericin B

Broadest-spectrum fungicidal polyene for Mucormycosis, invasive Molds, and Cryptococcus — significantly less nephrotoxic than conventional amphotericin B, but FORMULATIONS ARE NOT INTERCHANGEABLE MG-FOR-MG.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Remdesivir

IV antiviral for selected hospitalized COVID-19 patients; benefit depends on disease stage, oxygen requirement, immune status and current guideline context.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Isavuconazole

Mold-active triazole used for invasive aspergillosis and mucormycosis; notable for shortening rather than prolonging QT and for fewer cyclodextrin renal-vehicle concerns than IV voriconazole.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Foscarnet

Toxic IV antiviral for resistant/refractory CMV or acyclovir-resistant HSV/VZV. Nephrotoxicity is the major dose-limiting toxicity: adequate IV hydration, frequent creatinine-based dose adjustment, and close calcium/magnesium/pot…

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Azithromycin

Macrolide used for atypical CAP coverage and selected infectious syndromes; QT and interaction considerations matter in ICU patients.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Oseltamivir

First-line enteral antiviral for hospitalized/critically ill influenza when susceptible; treatment should not be delayed for confirmatory testing when clinical suspicion is high during influenza circulation.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Ampicillin

Narrow beta-lactam important for susceptible Enterococcus faecalis, Listeria monocytogenes and selected streptococcal infections.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Anidulafungin

First-line echinocandin for candidemia and invasive candidiasis in critically ill patients — features unique non-enzymatic spontaneous chemical degradation, with no dosage adjustment required for renal or hepatic impairment per p…

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Ampicillin-Sulbactam

Broad beta-lactam/beta-lactamase inhibitor used for susceptible polymicrobial infections; high-dose sulbactam-based therapy is a temporary CRAB bridge only when sulbactam-durlobactam is not immediately available.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Eravacycline

Fluorocycline approved for complicated intra-abdominal infection with activity against many ESBL/CRE and anaerobic organisms; not a urinary or bloodstream drug.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Rezafungin

Once-weekly IV echinocandin. U.S. labeling (revised July 2026) indicates it for candidemia and invasive candidiasis in adults and patients >=12 years who have limited or no alternative options; the label notes limited clinical sa…

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Penicillin G

Narrow bactericidal beta-lactam for highly susceptible streptococci, clostridial infections, meningococcal disease and neurosyphilis when appropriate.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Cefepime-Enmetazobactam

FDA-approved as Exblifep for adult complicated UTI including pyelonephritis due to designated susceptible organisms. IDSA 2026 also considers cefepime-enmetazobactam an alternative for ESBL-E infections outside the urinary tract;…

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Cefazolin

High-value narrow beta-lactam for MSSA and streptococci; often preferred over vancomycin for susceptible MSSA bacteremia after source evaluation.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Metronidazole

Potent obligate anaerobic bactericidal agent for intra-abdominal infections, CNS abscesses, and trichomoniasis — requires avoiding redundant double anaerobic coverage when paired with Pip-Tazo or Meropenem.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Polymyxin B

Toxic salvage Gram-negative agent; IDSA 2026 retains polymyxin B only as an alternative component for selected invasive CRAB, not as preferred routine therapy.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Fluconazole

Excellent-bioavailability azole useful for susceptible Candida step-down and cryptococcal consolidation/maintenance; not reliable for molds.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Daptomycin

Rapidly bactericidal cyclic lipopeptide used for selected MRSA bacteremia/right-sided endocarditis and VRE infections; monitor CPK and do not use it to treat typical alveolar pneumonia because pulmonary surfactant markedly inhibi…

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Clindamycin

Protein-synthesis inhibitor with anaerobic and Gram-positive activity; in ICU practice it is especially valuable as adjunct toxin-suppression therapy for selected invasive GAS/clostridial syndromes.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Minocycline

Tetracycline with activity against selected CRAB and Stenotrophomonas isolates; susceptibility testing and infection site are essential.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Plazomicin

Next-generation aminoglycoside active against many aminoglycoside-resistant Enterobacterales; role is limited by nephrotoxicity, availability and lack of activity against MBL-mediated co-resistance patterns in some isolates.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Colistin (CMS)

Colistimethate is the inactive prodrug of colistin; dosing-unit conventions vary and renal replacement profoundly complicates exposure. Reserve for resistant Gram-negative infection when safer active agents are unavailable.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Tobramycin

Concentration-dependent aminoglycoside with strong antipseudomonal activity; ICU use requires individualized PK/TDM because nephrotoxicity and altered Vd are common.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Tigecycline

Tissue-distributing glycylcycline with activity against many resistant Gram-positive and Gram-negative organisms, including selected CRE/CRAB; low serum/urinary exposure limits bloodstream/UTI use, and the U.S. label does not ind…

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Aztreonam-Avibactam

FDA-approved as Emblaveo with metronidazole for adults with limited/no alternatives for complicated intra-abdominal infection caused by designated susceptible Gram-negative organisms. Separately, IDSA 2026 recommends aztreonam-av…

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Gentamicin

Concentration-dependent Gram-negative agent with selected synergy uses; nephrotoxicity/ototoxicity and TDM make it a specialist ICU drug.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Levofloxacin

Respiratory fluoroquinolone with excellent bioavailability and antipseudomonal activity at higher dosing, balanced against significant class toxicities.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Ertapenem

Once-daily Group 1 carbapenem for ESBL Enterobacterales, cIAI, and cUTI in stable patients — NOT an antipseudomonal agent, and requires caution in severe septic shock / hypoalbuminemia due to altered protein binding.

Dosing • renal/CRRT • toxicity • interactions →
Full medication monograph

Fosfomycin IV

IV fosfomycin (CONTEPO) is now U.S.-approved for adults with complicated UTI, including acute pyelonephritis, caused by susceptible Escherichia coli or Klebsiella pneumoniae. Do not extrapolate this labeled indication to other MD…

Dosing • renal/CRRT • toxicity • interactions →

Evidence & bedside-use boundary

This Masterclass teaches selection and reasoning. Exact dosing, concentration, infusion preparation, renal/hepatic/RRT adjustment and monitoring must be checked in the linked medication monograph and the institution's current formulary/protocol. Local resistance patterns and regulatory drug availability can change faster than a static teaching page.

IDSA 2026 Guidance on Antimicrobial-Resistant Gram-Negative Infections
Mechanism-directed treatment of ESBL, AmpC, CRE, DTR Pseudomonas, CRAB and S. maltophilia.